Polynitrodiols



United States Patent 3,000,958 POLYNITRODIOLS Marvin H. Gold and Gustave B. Linden, Pasadena, Calif., assignors to Aerojet-General Corporation, Azusa, Calif., a corporation of Ohio No Drawing. Filed July 25, 1957, Ser. No. 675,798 8 Claims. (Cl. 260-584) This invention relates to new and useful polynitro diols and to a method for their preparation. In particular, this invention is directed to polynitro diols having the general formula:

wherein A and A are lower alkylene or lower nitroalkylene radicals, at least one A being a nitroalkylene radical.

The polynitro diols of our invention find valuable use as intermediates in the preparation of high explosive compounds. They readily condense with the nitro isocyanate compounds such as 3,3,3-trinitropropyl isocyanates, according to the method disclosed in assignees copending United States patent application Serial No. 479,656, filed January 3, 1955, to form polyritro carbamate compositions which are useful as high explosives. For example, 4,4,6,8,8-pentanitro 6 aza-1,ll-undecanediol condenses with 3,3,3-trinitropropyl isocyanate to form N,N'-bis-(3, 3,3-trinitropropyl) 4,4,6,8,8 pentanitro 6 aza 1,11- undecylene dicarbarnate. The compounds thus prepared are useful as high explosives and can be used in any conventional explosive missile, projectile, rocket, or the like, as the main explosive charge. An example of such a missile is disclosed in United States Patent No. 2,470,162 issued May 17, 1949. One way of using the high explosives in a device such as that disclosed in United States Patent No. 2,470,162 is to pack the crystalline explosive in powder form into the warhead of the missile. Alternatively, the crystals can be first pelletized and then packed. A charge thus prepared is sufliciently insensitive to withstand the shock entailed in the ejection of a shell from a gun barrel or from a rocket launching tube under the pressure developed from ignition of a propellant charge, and can be caused to explode on operation of an impactor timefuse mechanism firing a detonating explosive such as lead azide or mercury fulminate.

It is well known that acyl halides may be reduced to their corresponding alcohols with reducing agents such as lithium aluminum hydride, and hydrogen in the presence of a catalyst. However, these conventional reducing agents all possess such strong reducing properties that the destruction of functional groups, such as aliphatic nitro groups, usually accompanies the reduction of the carbonyl group. This method is further complicated by the sensitivity of nitro groups to basic media, hence these reducing agents, although capable of effecting the reduction, nevertheless have many undesirable features making it advantageous to find some more convenient method.

We have now found that polynitro diols can be prepared from their corresponding diacyl halides by reduction with sodium borchydride in accordance with the general reaction scheme set forth below:

0 N0 0 N0 H i! I XCA-NA-CX HOCH2ANACH2OH wherein A and A are lower alkylene or lower nitroalkylene radicals, at least one A being a nitroalkylene radical, and X is a halogen radical.

The reduction is efiected by adding a solution of a Intro-containing acyl halide to a suspension of sodium borohydride.

Optimum results are obtained using a suspension of 3,000,958 Patented Sept. 19, 1961 powdered sodium borohydride, about 200% excess, in an inert solvent such as dioxane.

1,4-dioxane is the preferred solvent due to its inert be havior and volatility. Any insert organic solvent can be used such as 2,4-dimethylsulfolane; however, dioxane is preferred since it can be separated from the product with greater ease.

The compounds thus produced are obtained in a relatively pure form from the reaction mixture by hydrolyzing the sodium borohydride and its oxidation products in the aqueous phase, with a mineral acid, and recovering the product by crystallization, extraction or distillation from the non-aqueous phase.

The following example is presented to more clearly illustrate our invention. This example is presented purely as a means of illustration and does not in any way define either the limits or the scope of our invention.

EXAMPLE 1 Preparation of 4,4,6,8,8-pentanitr0-6-aza-1,1]-

undecanediol A reactor was charged with 35 ordinary glass marbles, 150 gm. finely powdered sodium borohydride and 2 liters absolute dioxane. With stirring, 1500 ml. dioxane was removed by distillation at which time the distillate was no longer basic. After cooling to room temperature, a solution of 1.5 ml. glacial acetic acid in 15 ml. dioxane was added dropwise. A solution of .3 mole 4,4,6,8,8- pentanitro-6-aza-l,ll-undecanedioyl chloride was added dropwise over a period of about two hours. The temperature was maintained in the range of about 2226 C. The mixture became very viscous and 300 ml. dioxane was added at the mid-point. The cream colored mixture gradually became thinner, and after a total of 26 hours was cautiously poured into a stirred mixture of 400 ml. conc. hydrochloric acid and excess ice. During the hydrolysis a grey oil was isolated by filtration and the aqueous dioxane filtrate was extracted with ether and benzene and crystallized from methylene chloride. The product was dissolved in absolute ethanol, benzene and cyclohexane and treated with decolorizing carbon. The solution was cooled and the resultant crystals isolated, washed with a cold solvent mixture and dried. The yield was and the product 4,4,6,8,8-pentanitro-6-aza,1, ll-undecanediol had a melting point of 106108 C. The elemental analysis of the product was as follows:

Calculated: percent C, 28.99; percent H, 4.38; percent N, 20.29. Found: percent C, 29.24; percent H, 4.36; percent N, 20.68.

The polynitro diacyl halides used as starting materials in the practice of our invention are prepared from their corresponding acids by conventional means. The acids, for example, 4,4,6,8,8-hexanitro-6-aza-1,ll-undecanedioic acid, are prepared by hydrolysis of their corresponding esters which are prepared by the addition of a nitro-containing ester, having a labile hydrogen radical, to an unsaturated nitro-containing ester in accordance with the method disclosed in assignees ccpending application No. 337,211, filed February 16, 1953, now abandoned.

It is apparent that by merely selecting an appropriate polynitro substituted diacyl halide any member of this new class of polynitro diols can be prepared by reducing it with sodium borohydride in accordance with the teachings of our invention. For example, 4,6,6-trinitro-4-aza- 1,9-nonanediol is prepared by reducing 4,6,6-trinitro-4- aza-1,9-nonanedioyl chloride with sodium borohydride.

It will be appreciated by those skilled in the art that other members of this new class of compounds can be prepared in the same manner simply by reacting appropriate starting materials. It is preferred in the practice of our invention to utilize polynitro acid chlorides as starting materials for reasons of cost and convenience, how- 3 ever it should be understood that any of the acid halides can be used. It will also be appreciated that reaction temperatures are not critical in the practice of our invention, and that both higher and lower temperatures and conditions can be used if desired without affecting the course of the reaction.

This application is a continuation-in-part of our copending US. patent application Serial No. 392,471, filed November 16, 1953, now abandoned.

We claim:

1. As compositions of matter the polynitro diols having the formula:

wherein A and A are radicals selected from the group consisting of lower alkylene and lower nitroalkylene radicals, at least one being a nitroalkylene radical.

2. As a composition of matter 4,4,6,8,8-pentanitro-6- aza-1,l1-undecanediol having the structural formula:

3. As a composition of matter 4,6,6-trinitro-4-aza-1,9- nonanediol having the structural formula:

4 4. The method of preparing polynitro diols having the formula: V

HOCHz-AN-ACH2OH which comprises reducing a polynitro diacyl halide having the formula:

with sodium borohydride wherein A and A are radicals selected from the group consisting of lower alkylene and lower nitroalkylene radicals, at least one -A being a nitroalkylene radical and X is a halogen radical.

5. The method of claim 4 wherein the reaction is conducted in the presence of an inert organic solvent.

6. The method of claim 4 wherein the reaction is con ducted in the presence of 1,4-dioxane.

7. A method of preparing 4,4,6,8,8-pentanitro-6-aza- 1,11-undecanediol which comprises reducing 4,4,68,8- pentanitro-6-aza-1,1l-undecanedioyl chloride with sodium borohydn'de.

8. A method of preparing 4,6,6-trinitro-4-aza-1,9-nonanediol which comprises reducing 4,6,6-trinitro-4-aza-1,9- nonanedioyl chloride with sodium borohydride.

Hurd: Chemistry of the Hydrides, John Wiley and Sons, Inc., New York (1952), page 162.

Shechter etal: J.A.C.S., vol. 74 (1952), pages 3664-8. 

1. AS COMPOSITIONS OF MATTER OF POLYNITRO DIOLS HAVING THE FORMULA: 